A 12-month-old girl is brought to the immunisation clinic for her routine vaccines. On review of her vaccination card, it is noted that she received BCG at birth, but the DPT series was incomplete—she received only DPT-1 at 6 weeks and DPT-2 at 10 weeks. She has not received any other vaccines since DPT-2. According to the National Immunisation Schedule of India, what is the most appropriate next step?

Explanation

## DPT Series Completion in Delayed Vaccination **Key Point:** Once DPT-1 and DPT-2 have been administered, DPT-3 should be given regardless of interval, and the booster schedule is based on completion of the primary series, not on age alone. ### NIS DPT Schedule Overview | Dose | Age | Interval from Previous | |------|-----|------------------------| | **DPT-1** | 6 weeks | — | | **DPT-2** | 10 weeks | 4 weeks | | **DPT-3** | 14 weeks (ideal) | 4 weeks; but if delayed, give as soon as possible | | **DPT-B1 (1st Booster)** | 18 months | 6–12 months after DPT-3 | | **DPT-B2 (2nd Booster)** | 5–6 years | — | **High-Yield:** The NIS does NOT require restarting the series if DPT-1 and DPT-2 have been given, even if the interval is prolonged. The child is considered to have received 2 doses and should proceed directly to DPT-3. ### Interval Rules for Catch-Up Vaccination 1. **Minimum interval between doses is respected** — but if exceeded, the next dose is given as soon as possible without restarting. 2. **Doses already given count** — there is no "reset" of the series in DPT vaccination. 3. **Booster timing** — DPT-B1 is given 6–12 months after completion of the primary series (DPT-3), not based on age. **Clinical Pearl:** At 12 months, this child has received 2 doses of DPT. She should receive DPT-3 immediately at this visit. After DPT-3 is given, DPT-B1 should be scheduled for 6–12 months later (i.e., between 18–24 months of age). **Warning:** Do not confuse "delayed vaccination" with "restarting the series." In DPT, as long as at least 2 primary doses have been given, the series is not restarted; the next dose is given as soon as possible. ### Additional Vaccines at 12 Months At this visit, the child should also receive: - **Measles-1** (if not given earlier) - **OPV booster** (if primary series complete) - **IPV booster** (if applicable) - **Hepatitis B booster** (if primary series complete) - **PCV booster** (if primary series complete) [cite:IAP Immunisation Schedule 2024; Park 26e Ch 6]